Following the guidance of a U.S. Supreme Court justice, Attorney General Tom Horne has threatened to sue an effectively non-existent federal commission if it doesn’t put Arizona’s requirement of proof-of-citizenship on federal voter registration forms.

Horne is giving the U.S. Election Assistance Commission until Aug. 19 to act, stating in a July 26 letter to the commission’s acting executive director, Alice Miller, that Louisiana recently got approval to put requirements specific to the state on the federal forms.

There was no frenzy at Maricopa County Elections upon word of Monday’s U.S. Supreme Court ruling forbidding Arizona from requiring proof of citizenship for voters using federal registration forms. Nor does the decision mean voters will encounter changes in the way they register.

In the first of two widely-anticipated voting rights decisions from the U.S. Supreme Court this month, the justices struck down Arizona’s voter-imposed law requiring residents to show proof of citizenship in order to register to vote in federal elections.